Asset Management Expense Cap, Percentage

No definition available.

Name:	ladr_AssetManagementExpenseCapPercentage
Namespace Prefix:	ladr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Asset Management Fees, Percentage

+ References

No definition available.

+ Details

Name:	ladr_AssetManagementFeesPercentage
Namespace Prefix:	ladr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Loans Receivable With Fixed Rates Of Interest, Percentage

+ References

No definition available.

+ Details

Name:	ladr_LoansReceivableWithFixedRatesOfInterestPercentage
Namespace Prefix:	ladr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Loans and Leases Receivable, Related Parties, Mortgage Participation Purchased

+ References

No definition available.

+ Details

Name:	ladr_LoansandLeasesReceivableRelatedPartiesMortgageParticipationPurchased
Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Loans and Leases Receivable, Related Parties, Participating Mortgage Loan

+ References

No definition available.

+ Details

Name:	ladr_LoansandLeasesReceivableRelatedPartiesParticipatingMortgageLoan
Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Real Estate Properties, Ownership Interest

+ References

No definition available.

+ Details

Name:	ladr_RealEstatePropertiesOwnershipInterest
Namespace Prefix:	ladr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Related Party Transaction, Related Party Purchases of Shares From Shareholders

+ References

No definition available.

+ Details

Name:	ladr_RelatedPartyTransactionRelatedPartyPurchasesofSharesFromShareholders
Namespace Prefix:	ladr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Area of land held.

+ References

No definition available.

+ Details

Name:	us-gaap_AreaOfLand
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

Name:	us-gaap_InterestExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest income earned from interest-bearing assets owed to the entity by related party.

+ References

No definition available.

+ Details

Name:	us-gaap_InterestIncomeRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Cost of the investment.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=63488139&loc=d3e12121-115841

+ Details

Name:	us-gaap_InvestmentOwnedAtCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(e))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

Name:	us-gaap_LoansAndLeasesReceivableRelatedParties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfRealEstateProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_CounterpartyNameAxis=ladr_HallettsInvestorsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ladr_MezzanineLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=us-gaap_GuarantorSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=ladr_RelatedReserveIVLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=ladr_BParticipationInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=ladr_BrickellHeightsCommercialLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_MultifamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ladr_BrickellHeightsCommercialLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_CorporateJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=ladr_RelatedSpecialAssetsLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CounterpartyNameAxis=ladr_TheRelatedGroupofFloridaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=ladr_RelatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

RELATED PARTY TRANSACTIONS (Details) $ in Thousands		12 Months Ended
RELATED PARTY TRANSACTIONS (Details) $ in Thousands	Mar. 03, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jul. 06, 2017 USD ($) property	Mar. 13, 2017 USD ($)	Oct. 18, 2016 USD ($)	May 20, 2015 USD ($) a
RELATED PARTY TRANSACTIONS
Interest expense		$ 146,118	$ 120,827	$ 113,303
Halletts Investors LLC \| Mezzanine loan
RELATED PARTY TRANSACTIONS
Loans receivable from related party								$ 25,000
Percentage of loans receivable with fixed rates of interest								9.00%
Interest income on loans			$ 1,000	$ 1,400
Three Limited Liability Companies \| Halletts Investors LLC
RELATED PARTY TRANSACTIONS
Area of land (in acres) \| a								9.66
Affiliated Entity
RELATED PARTY TRANSACTIONS
Investment in mutual fund		$ 900					$ 10,000
Fee earned on assets under management (as percentage)		0.75%
Fund's cap expense (as percentage)		0.95%
Affiliated Entity \| Related Reserve IV LLC \| B Participation Interest
RELATED PARTY TRANSACTIONS
Percentage of loans receivable with fixed rates of interest						17.00%
Interest expense		$ 500
Mortgage loan participation purchased by related party						$ 4,000
Participating mortgage loan amount						$ 136,500
Affiliated Entity \| Brickell Heights Commercial LLC \| First mortgage loan
RELATED PARTY TRANSACTIONS
Loans receivable from related party					$ 21,000
Interest income on loans		$ 300
Multi-family \| Affiliated Entity \| Brickell Heights Commercial LLC
RELATED PARTY TRANSACTIONS
Number of real estate properties \| property					2
Brickell Heights Commercial LLC \| Consolidated Joint Venture \| Related Special Assets LLC
RELATED PARTY TRANSACTIONS
Ownership Interest (percent)					80.00%
Brickell Heights Commercial LLC \| Consolidated Joint Venture \| The Related Group of Florida
RELATED PARTY TRANSACTIONS
Ownership Interest (percent)					20.00%
Class A common stock \| Related
RELATED PARTY TRANSACTIONS
Related party purchases of shares from shareholders	$ 80,000